The imperative of time

With the launch of its FIT7A digital load cell, HBM has opened a new chapter in dynamic weighing and industrial metering applications. With its higher precision (Class C4 according to OIML R 60), this load cell enables the extension of strain gauge technology to applications reserved until now for electromagnetic force compensation technologies (EFC).

And that while maintaining the key benefits of strain gauge transducers, namely sturdiness proven over decades of use under rough industrial conditions, a high sampling rate (180 weighings/min.) and above all a price less than 60% of that of the EFC technology.

With the FIT7A, HBM is underlining its know-how in the field of digital strain gauge transducers. At the very beginning of the 2000s, HBM was the first manufacturer to bring a dynamic load cell with onboard electronics to the market. And the French industries were among the very first to adopt this technology.

Time and space as critical factors for machine design

One of the first French companies that used our load cells was NTN-SNR, an internationally known manufacturer of bearings and guides with activities in all the markets (automotive, aerospace, agriculture, railways, industrial equipment for quarries, mines, etc.). The application focuses on checking the exact quantity of grease injected into the bearings. This quantity is critical, since the service life of the bearing – and indeed the safety of the equipment on which it is installed – is dependent on it (overheating could be dangerous). The quantity of grease is metered by means of a piston pump; but for greater safety, NTN-SNR prefers to check this by double weighing the bearing, before and after greasing. Until then, the double weighing of the bearings had been performed using high-precision laboratory balances.

As this inspection station was a bottleneck in the production process, NTN-SNR looked for a better solution and purchased a machine that performs both the injection of the grease and the double weighing of the bearings. It was on this machine that the FIT transducer was installed. The machine was designed and manufactured by BEA. With two challenges to address, recalls Philippe Viallet, who manages the company:

“First there was the imperative of time: The whole operation (greasing and double weighing) had to be completed within a few seconds. Then there was also the question of space.”

The FIT7A load cell installed under the inspection point

NTN-SNR bearing

Bearing greasing inspection point

Long-time proof of reliability

For this machine, the technical solutions chosen at that time appear audacious today. Even though the integration of digital techniques into the sensors already appeared inevitable, the FIT digital load cell from HBM was nevertheless an unprecedented step for dynamic load cells. It needed a great deal of confidence to install this on a critical production machine that had to operate without interruption, around the clock.

For Philippe Viallet, this choice demonstrated higher confidence in the manufacturer than the confidence shown in the technology. According to him,

“This choice of technology was taken together with our customer, NTN-SNR. And if we didn’t hesitate at that time, it was because it was HBM that proposed this major advance.

HBM was a specialist for load cells who we had known for a long time and who had never been in the habit of making promises lightly. Furthermore, the transducer was based on the strain gauge technology that had very much proved its worth when it came to sturdiness. As we know now, the future proved them right – the FIT load cell has kept all its promises. In effect, for an equipment supplier, an application that has functioned for more than 10 years constitutes proof of reliability, particularly on a machine intended for production around the clock. This assurance of a long service life therefore induced NTN-SNR to renew its confidence in the latest version of the digital load cell, the FIT7A, for installation on a new machine:

“When a concept has proved its worth in the field, you gain precious time by duplicating this type of installation for future projects, while ensuring a solid technical basis.”

That is how a customer’s confidence in HBM and its dynamic weighing solutions has grown, and how it has perpetuated over time. This positive experience and the success of an audacious project culminating in the satisfaction of the users makes us want to offer innovative and ever more efficient solutions in the field of dynamic weighing.